It's customary for a Bomberman game to reuse old enemies, but some of the foes and bosses haven't been seen in a long time! Foes from Super Bomberman include Denkyun, Pakupa, Moguchan, Keibin, Kierun, and possibly Yoroisu.
Also among the grunts are Icetower and Machineda from Super Bomberman 3, Bomberwan from Bomberman '93, and Skunp and Missile Man from Super Bomberman 4. Pretty sure this flower is from something, too; '93, probably?
Even a good chunk of the bosses are lifted from prior games! Boss 3 is a creepy remake of Grub Robs from Bomberman '94, Bosses 2 and 6 are redesigns of Gabara and Zankokuran from Bomberman '93, and Boss 4 is a revisit of Ponchos, the cacti Togetoge and Chikuchiku from Super Bomberman 3!
For whatever reason, the Western boxart is an edit of the Japanese cover of Bomberman Battles.