Mega Man IV for the Gameboy is very similar to its immediate predecessor, Mega Man III. It’s a game with uneven, often unfair difficulty, and which doesn’t add enough to the formula to really justify its existence. At this point, the Mega Man series on Gameboy was clearly getting stale.
As with previous Gameboy Mega Man games, MMIV is split into two sets of four bosses. Capcom was especially lazy this time, presenting all eight bosses in the exact order you’ll likely want to fight them. The first set of bosses, from the NES Mega Man 4, are fine, but the game begins to fall apart in the second half. The latter stages experiment with more side paths and non-linearity than is normal for a Mega Man game, but these stages tend to be overlong and filled with exacting jumps and instant kill traps. They are, in short, not very fun.
Mega Man IV also suffers from general slowness. The game is plodding, and can be unresponsive as a result. This is not what you want in an exacting game like Mega Man, especially when you’re replaying a stage specifically because the slowness caused you to miss some pixel-perfect jump.
It’s not all bad, though. Mega Man IV makes decent use of its weapon selection, and the special new weapon designed for this game is very useful during the limited time you have it. The game is very generous with items and lets you buy more tanks of various types, though they don’t help with pits, spikes, and other death traps. Beat also makes a return here, useful but not as overpowered as in some of his NES appearances.
On the whole, Mega Man IV is more Gameboy Mega Man, and you should know what to expect if you’ve played previous games in the series. The snappy gameplay of the NES is too much for the Gameboy, and the challenge has largely been changed to that of memorization and perfect jumping. It’s not a terrible game, but it doesn’t do the series justice, either.