TL;DR Fan-made standalone game featuring most Gen I - Gen VI Pokemon.
http://www.pokemonzetaomicron.com/
-> Standalone Pokemon Fan Game. No need to download any ROMs or hacks, just the game!
-> ~2.5 regions (final game will have 20 badges, ATM there's 18).
-> Gen VI Pokemon, Gen V Mechanics, and Gen III graphics (you can update the sprites to be moving, though).
-> 40+ hours of original Gameplay.
-> http://pokemonzetaomicron.com/
Positives:
+99% of items are purchasable (Dusk Balls, Choice Scarfs, basically everything except Master Ball and PP items >_>)
+You can see your EVs and IVs easily, not to mention IVs are changeable (it is a high price...but still).
+HM items. Never carry a Bidoof again.
+Missingo is catchable. There are a handful of other Fakemon too like Ausitto (Ditto evolution that learns Sketch and Transform).
+You can trade with yourself
+Kanto starters are available in wild and all other starters are easily obtainable in your Secret Base
+Shadow Pokemon
+Delta Pokemon (think trading card game, aka Pokemon with different types).
+Pokemon follow you!
+Plot that's somewhat interesting (at least more than the original games).
+Your rival has so much swag it's not even funny.
+Save files transfer through patches.
+Game is CHALLENGING. You HAVE to use STRATEGY (!!!!). Pokemon three levels under you give hardly any experience. You get 90% of your experience from trainer battles. Towards the end of the first region you find yourself battling trainers +10/20 levels above you.
+Level cap raised to 120 due to the sheer amount of content.
Negatives:
-Lousiest starters ever (Horsea, Magby, and Bellsprout). On the bright side, they're all balanced in stats and receive other goodies (like....Bellsprout gets Spore).
-The multiplayer trading/battling server is intermittently on/off.
-Game is 85% done. Right now it's still over 50 hours of gameplay.
-That being said, animations aren't complete for many moves, and most of the Gen 6 follow sprites aren't done.
http://www.pokemonzetaomicron.com/
-> Standalone Pokemon Fan Game. No need to download any ROMs or hacks, just the game!
-> ~2.5 regions (final game will have 20 badges, ATM there's 18).
-> Gen VI Pokemon, Gen V Mechanics, and Gen III graphics (you can update the sprites to be moving, though).
-> 40+ hours of original Gameplay.
-> http://pokemonzetaomicron.com/
Positives:
+99% of items are purchasable (Dusk Balls, Choice Scarfs, basically everything except Master Ball and PP items >_>)
+You can see your EVs and IVs easily, not to mention IVs are changeable (it is a high price...but still).
+HM items. Never carry a Bidoof again.
+Missingo is catchable. There are a handful of other Fakemon too like Ausitto (Ditto evolution that learns Sketch and Transform).
+You can trade with yourself
+Kanto starters are available in wild and all other starters are easily obtainable in your Secret Base
+Shadow Pokemon
+Delta Pokemon (think trading card game, aka Pokemon with different types).
+Pokemon follow you!
+Plot that's somewhat interesting (at least more than the original games).
+Your rival has so much swag it's not even funny.
+Save files transfer through patches.
+Game is CHALLENGING. You HAVE to use STRATEGY (!!!!). Pokemon three levels under you give hardly any experience. You get 90% of your experience from trainer battles. Towards the end of the first region you find yourself battling trainers +10/20 levels above you.
+Level cap raised to 120 due to the sheer amount of content.
Negatives:
-Lousiest starters ever (Horsea, Magby, and Bellsprout). On the bright side, they're all balanced in stats and receive other goodies (like....Bellsprout gets Spore).
-The multiplayer trading/battling server is intermittently on/off.
-Game is 85% done. Right now it's still over 50 hours of gameplay.
-That being said, animations aren't complete for many moves, and most of the Gen 6 follow sprites aren't done.