The remake of Bonk's Adventure is like Castlevania? --- Owner of The NES, SNES, N64, GCN, Wii, SMS, GEN, TG16, PSX, PS2, PS3, XBOX, 360, GB, GBC, GBA SP, GB Micro, DS, DSLite, PSP and a lot of crappy games. --BLINGO!
this might be a stretch, but what about Mega Man Network Transmission? i havent played too much of it (just boght it sort of recently, in fact) but its a 2D side-scroller with many different weapon types/items you acquire that help you defeat enemies, but more importantly, help you progress through the levels, for instance: bombing down certain walls to create shortcuts.