Single player, by 
It’s unclear what makes these “coop” levels. They’re fully linear…the path never splits in two like you might imagine. Not a lot of high jumps where one player should stand on another’s head. No trigger crates or anything are available to encourage one player to help another. No multiplayer-only events that I notice. Many coin warps (one in almost every level), which are one of the least coop-friendly mechanics available.
But they’re solidly… okay. The graphics are more or less functional, and the layouts are mostly horizontal but do have moments of vertical movement that force you to pay attention to the level instead of holding the run key. Enemies are varied and generally appropriate to their tilesets; only butterflies are seemingly omnipresent but they’re so rare in levels outside this pack that I’m inclined to forgive this detail.
Ammo is pretty good too, despite the occasional misstep of placing powerups (ostensibly inside coin warp areas) where they may be shot by electroblaster. This pack adapts a common theme from early (think J2C-era) single player packs where it pretends the player has never played JJ2 before and so all mechanics need to be reintroduced, from ammo types to gems and savepoints… this conceit has never once made the least bit of sense, of course, but it’s cute enough, despite the occasional english issue. Even after all the weapons have been introduced, the pack mostly fits each level with only one weapon type, an interesting design holdover from the official JJ2 levels which maybe doesn’t get used as often by other people. There’s a surprisingly good effort to match enemies and layouts to the weapons most useful against them.
I can’t claim this pack does anything memorable. The levels are disconnected with not even a hint of storyline to justify the random assortment of tilesets, and the layouts are never spectacular. But there’s a lot of effort on display here nonetheless. Many of the levels do genuinely have features unique to them, attempting to match the design to the graphics. That kind of variety is a great thing. This is promising. THE COOLEST COOP LEVELS #2 will surely be better still.
