I finished the Arcade Game (NES). Easier than the first NES games, but still tough. Konami and many game companies hated kids renting these games. Who's idea was it for a single score system. Every enemy is worth 1 point. Even the tougher variants and mini bosses. If you play the Japanese version, your jump kicks do double the damage as a special attack, and it goes for pinball scoring. This makes it easier to gain extra lives. You fight less enemies in the Japanese version too. I beat the game with 1 life left. This collection does the unfortunate thing of locking achievements behind the USA versions of games only. You want to the achievement of beating the game? You have to play and beat the American version! Beating the Japanese versions does nothing. What is with Konami Collection games doing this? Castlevania and Contra Collection did the same thing! You can still use the lives cheat and not get penalized, so their are some saving graces.
I will say this game and Manhattan Project have variety in level design and enemy types. MP has the most and better variety of course, but it's still amazing. All that enemy variety, even though you're fighting the same Foot Ninjas 80-85% of the time, but a different color outfit and weapons. Though the further you go, most of the purple Foot Ninjas get additional moves, along with some the colored variations. They even have level specific ones where they will throw snowballs or sand in your eyes depending on the game. Goes to show what you can accomplish with limited hardware.