Spring Breeze is essentially a reduced version of the original Kirby's Dreamland easy mode, only with ability-copy allowed. It shouldn't give you much trouble.
DynaBlade is longer than Spring Breeze, but not tremendously more difficult. There are in fact two hidden ability gallery stages, contrary to the manual's hint. One is off of stage 2. Use Mirror/Smirror to hit the bomb block on the second floor of the first room inside the castle to reveal a door leading to the switch. The other off of stage 4, I believe in the hidden TAC/copy power room to the left of where you start in the lava block area.
Great Cave Offensive is long and tedious, but fun. To get all treasures, keep your eyes peeled for drop-thru floors (e.g. waterfall block in second area of bird/jet palace), hidden doorways (e.g. in candle-lit rooms of castle towers) and places where you need a helper to progress (e.g. underwater fuse and post-under-hanging-platform, both in castle). Some day I should write a full treasure list...
Revenge of MetaKnight is an interesting game. All stages are timed, if somewhat leniently, so just keep moving. If you die, time resets to an extent. The trickiest part of the game is the series of doors/switches in one of the later stages. Drop through the floor to backtrack and try again if you miss any, dashing and thrown weapons can help greatly. I'm not sure what happens if you actually defeat MetaKnight in the escape phase, the easiest approach is just to hop on Wheelie and dash tot he end of the stage, remembering you can infinitely multi-jump if youaccidentally misjump a wall or pit.
Milky Way Wishes is arguably the most entertaining game of the bunch. Find the hidden ability icons and you can use any generic power in the game whenever you want. Contrary to the manual and in-game guide, some powers can be obtained by swallowing enemies, but these are limited to the one-shot powers- Mic, Crash, Cook, Sleep and Paint. Also, remember you can't change abilities in boss rooms, so your first encounter with a boss is often your best opportunity to beat him.
Power icons are located:
Floria:
- [Ice] At the very start of the stage, in winter.
- [Fighter] In the hollow after the first tree either in summer when the water is gone or in winter when the water is frozen.
- [Cutter] Under the second tree in summer.
Aquatiss:
- [Parasol] In the middle of the first area, hit a submerged bomb block and follow the smoke to where it opens a door above water.
- [Sword] In the third area (nighttime background, water surrounding a small palace structure), take the door in the middle of the palace structure, work your way past the spikes and Blade Knights, and defeat the sub-boss for the power. Use Parasol v+Y to break the blocks leading down. It might be a good idea to save the tomato for after the sub-boss.
- [Beam] In the penultimate underwater maze, take the branches down, right, down, right, and up to reach the icon.
Skyhigh:
- [Jet] Break the star block in the ceiling of the windy passage in the first area (use Fighter's uppercut, Parasol, Beam or Sword's midair spin) and fly to the door.
- [Wheel] Shortly after the Jet room, use Jet to light the fuse on the ground. Use one charge dash to go from the fuse to the top of the slope to its right and one charge dash off the top of the slope to clear the remaining enemies and reach the cannon. The cannon blasts you to the Wheel room.
- [Wing] In the 'maze' following the first area, take the right door in the first room to a room with mountains in the background, the center door there to a room with springtime landscape in the background, and the left door there to a room with a starry background. The center door here with three large stars above it leads to the ability. The right door from the mountain room, incedentally, leads to the gate to the boss.
Hotbeat:
- [Fire] In the first area, hit the bomb block on the ceiling in the middle of the 'S' bend (Wing works well). Retrieve the lollipop from the top of the 'S,' backtrack, and fly up through the lava released by the bomb to the door. If you used Jet to get up, it will be easy to blast up through the following vertical room to the door with the icon.
- [Suplex] In the second portion of the stage, use a Fighter uppercut to break through the stone blocks above the one patch of grass in the area. Beat the sub boss behind the door for the icon.
Cavios:
- [Bomb] Defeat Poppy Bros Sr. in the upper-middle region of the first cave area.
- [Hammer] Defeat Bonkers in the middle-right region of the first area.
- [Stone] Destroy the bomb block above where you start in the second (blue) cave. Swim up through the opening and hit the switch on the right to open the door you probably saw to the right of where you started.
Mecheye:
- [YoYo] In the third (metal maze) area, take the upper path and use Wing to fly to the upper door of the windy room. The icon is in a room at the bottom of the elevator (get on, and just hold v, trying to make sure any helper you have doesn't get stuck above the elevator or it will move back up on its own).
- [Plasma] Take the elevator in the fourth area all the way to the top and fight the sub-boss on the left for the icon. Incedentally, use a moderate-level Plasma charge shot to hit the bomb block to the right of the elevator at this level and collect 3 1ups.
Halfmoon:
- [Mirror] In the third (starry) area, keep to the bottom of the screen until you spot a single star block in a pit. Drop down to it and remove it with some ability that allows a quick arial recovery- the door to the ability is directly below, but there is no ground underneath it!
- [Ninja] In the fourth (windy) area, a little over half way to the top, hit one of the bomb blocks to open the way to the obvious door.
?:
- [Copy] There is a green star / diamond above the cloud planet Skyhigh. You can land on it. The ability icon is in the final room of the short TAC- and bomb-infested level. Be careful, because the room has no floor!
Some boss projectiles have associated powers.
- Cook's eggs grant Bird ability (at least to Helper contact...).
- Many falling rocks grant Stone ability.
- The Chameleon boss' paint balls grant Paint ability, a rare one-shot more or less equivalent to Crash.
Some abilities have moves which are difficult to discover without reading the in-game help screens. A few of the more interesting ones are:
- [Fire] You can direct Kirby's and Leo's fire breath with the D-pad. ^ or v will raise or lower its average angle slightly, but if you hold the direction opposite your facing for a few seconds the breath will decrease in range and increase in intensity until you become engulfed in a bonfire which does serious damage to any enemy on contact.
- [Fire] If you press Y in midair, you turn briefly into a wheel of fire with little combat value. However, if you press Y just before landing a jump, that fire wheel will roll along the ground at a good clip for about a screen's length.
- [YoYo] Press v, Y+^ (Y first, then add ^) as Kirby or Gim to do an impressive headstand to vertical spin-launch maneuver the game dubs a 'Gazer Spiral.'
- [Hammer] Kirby's the only one who can do this, but if you dash and press A (not Y!), you'll do a normal dash+Y spin, but then release your hammer. You'll lose Hammer power, but if the hammer hits anything, it does major damage. Most sub-bosses will lose at least half their life, Poppy Sr. can even be killed in one hit.
- [Sword] It's not too hard to find, but that spin move you do underwater can be triggered in midair by pressing Y in a dash-jump.
- [Plasma] Once you have a charge, just getting near an enemy is enough to deal moderate damage.
- [Bomb] Tap Y when adjacent to an enemy to plant a bomb on it. Dash and press Y to throw a bom straight forwards.
- [Jet] Jump when at full charge to carry the charge elsewhere. Press B in midair when fully charged to rocket upwards. Press Y in the middle of a horizontal dash to halt, releasing a strong, short-range 'Jet Cracker.'
Use guard (L or R) often. While most attacks can be avoided other ways, guarding nullifies direct hits from almost any attack in the game, which is especially useful in boss fights.
Parasol is one of the more undervalued Kirby abilities. Sword and Hammer seem better for close attack, but Parasol can hold its own in single hits, has strong dash and air+v attacks, and is unexpectedly useful underwater.
Know when to restore your Helper, when to recycle your Helper and when to let your Helper die. Contact with a generic-ability enemy will restore a dying Helper automatically. Contact with an ability item (press A to release Kirby's) will restore a Helper at any point, but costs Kirby an ability. Kirby's 'Suppin Beam' (press A without an ability) will turn a Helper into an ability item which can then be eaten and kept or turned into a new full-health Helper, but you'll have to risk losing any ability Kirby has to recycle a Helper in this way. Sometimes Kirby's ability is valuable enough that it's best just to go it alone if your Helper can't save himself.