Summary
Original CV title, but it's not as good as the console CV games of the time.
The Good
After playing many Castlevania games on many varied Nintendo systems, I found myself in front of an used copy of the Gameboy game "Castlevania II - Belmont's Revenge" in a game shop, and since I didn't try any old GameBoy CV game before (I have the GBA ones but that's another story), I figured out that I have missed something, and that I should buy that right away.
Shortly after plugging the cartridge into my GBA and starting a new game, I was surprised. This game effectively have a stage select screen ! Kinda remember me the Mega Man games. You can select between 4 stages initially (although you don't get the boss' ability or anything so it doesn't matter in which order you complete them).
After choosing one of them, my surprise continued. Unlike what I'd have expected, the graphics, music, game engine and overall ambiance found in this game is radically different from the NES CV games. The hero is smaller, his whip is shorter, and the traditional square bricks we love are gone. You go up down floors using a rope instead of using simply stairs (wow the hero is really strong).
Also he walks quite slowly, probably because the original Gameboy's LCD screen had terrible blur and this made fast scrolling looking horrible. Now we have GameBoy compatible hardware capable of rendering better graphics, so that's not really an issue, anyway. At first it seems terrible, but you'll get used to the controls quickly (at least I did).
I must admit that the graphics, although fully monochrome (what would you expect anyway ?) are overall detailed for the Gameboy standards, even it the sprites are not incredibly varied, the backgrounds are more detailed. There is nice effects like bridges collapsing and moving spikes, among a few others. The bosses are impressive (and for the most part hard).
The Bad
When you lose to a boss, you have to make your way back a *very* long way and this is kind of annoying. At least you get infinite continues and passwords, which is decent enough.
The last boss was just impossible for me to beat, but it may have been possible for other people ? At least I was able to made it to the last boss without any cheats, which is already great.
I didn't find the music really exciting or that it really filled the mod. In fact the music was rather bland and looped shortly, forcing me to mute the sound of my GameBoy at times. The scaring music right before bosses was decent tough. The sound effects weren't really varied or awesome but it's OK.
Finally, although the game is hard, it's really quite short, it has only 6 levels. Again I guess short games with few stages are the standard for the original GB.
The Bottom Line
It's really not the best Castlevania game out there, as the music is average at best, and WAY below the awesome music found in other Castlevania games. The gameplay is good so are the graphics (for the GameBoy of course), but it's a little too short and hard in my opinion. If sub-weapons were more effective and if you had less backtracking to do when losing it'd be okay, but it's not the case.
So overall while it's a cool little fun game, it just falls way below the Castlevania standards, and could result in a disappointment if you are excepting it to be as great as it's console counterparts of the same time area (Castlevania III and Super Castlevania IV are much awesome in my opinion). If you are a fan you'd still want to consider buying an used copy or emulate the game, else I'd say just pass and go playing better home console Castlevania games instead (there is great ones for the GBA/DS too if you like the Gameboy line).