I played through this via the Z/ZX Collection. Fun game with the checkpoints and being able to jump back in whenever you die especially against the bosses. The whole thing with levels being erased only happens with no save-assist I believe and this is an instance where you need to play this with it to enjoy it. Only issue I found is how you have to grind abilities/upgrades by slowly killing enemies in the same spot over and over to grind crystals for stuff like extra tanks and running faster. Pretty lame.