[Seshuma]

i want to hack this ROM but i don't know how to hack the genesis Roms  i hope someone can help me

[FAST6191]

What do you know how to hack? If you are familiar with something like the SNES then in many cases the megadrive/genesis is easier to hack, give or take the lesser state of the debugging emulators (I am not sure what we are suggesting right now for this). http://www.romhacking.net/documents/277/ covers hardware things pretty nicely.
There is no file system to pull apart and it is all in the ROM like most systems of the day and older, no set formats for things and space is likely to be an issue, though you do mostly dodge bankswitching and weird memory mapping which is nice. By similar token most tile editors if they are not highly specific (most aren't) will have a megadrive/genesis mode.

If you are not familiar with hacking then I am probably supposed to point you at http://www.romhacking.net/start/

Also what do you want to hack? Text, stats, high level logic in the game, graphics, music and levels probably all have rather different approaches. We can cover whatever you like but there is no point in spending 3 hours covering text editing if you want to edit some stats or make some cheats or something instead.

[Seshuma]

i want to make it harder i found this game has potential  yeah but its to easy i want to make  monsters stronger and faster and i want that the life up items are not so strong so u need 4 for one up and your own dmg  halved

[FAST6191]

I imagine all those are well within the realms of possibility, however I would not be surprised to find each and every one needs fairly extensive assembly hacking to get there, some might not but I have plenty of games that have all of those buried deep in code rather than stats or something more basic. Assembly hacking then being the final stage of learning to hack for most people. Though at the same time this would be a fantastic project/incentive to learn with.

I should also say monsters stronger and damage halved and health regen being harder all basically cover the same number, or same two numbers within a game. By all means edit all the components but if you say double monster health and half your damage you have actually just quadrupled the effective difficulty. If you knew that then apologies for stating the obvious but I had to mention it anyway.

[PresidentLeever]

Just putting this wishlist here, can't help with the hacking unfortunately;
-Jump shadow for Nigel
-Added friction if standing on an interactive object put on a moving platform so you don't fall off if you don't move with the platform
-Make it so the sword doesn't prioritize walls over enemies in narrow areas
-Improved AI for some later enemies like the bird guy mini-boss and knights
-Make it possible to avoid the gnome push in greenmaze
-Removed backtracking after getting that heart piece in the swamp shrine where you have to drop down a floor - the game should spawn a moving platform after opening the chest
-Skippable intro in-game cutscene
-New sounds for enemies that shouldn't scream when killed, like slimes
-No need to go into the menu to use a key on a locked door

[gadesx]

easy? If it's a hard game, or atleast I'm not too hardcore gamer for finish it without cheats lol