Horde 2.0
Horde 2.0 expands upon the Horde mode first implemented in Gears 2, then copied in many a game ever since. the original Horde pits players against 50 waves of Locust enemies, increasing their strength as the game goes on. if a player dies, they respawn at the start of the next wave (if his teammates survive, that is). Horde 2.0 adds in more strategic elements to the original; you still respawn at the next wave if you die and there's still 50 waves of Locust to fight. however, players earn cash as they progress through the waves, to spend on ammo crates, new weapons, and defenses such as barriers and turrets to help combat the enemies, as long as they have enough cash. the defenses can only be built or repaired in-between waves; the ammo crates can be bought whenever needed. another new feature are the boss waves. these come up every 10 waves, and include some large enemy in addition to smaller enemies.
this mode is just as addicting as the original, but later waves either take a very experienced Gears player or a whole team to keep going through the waves. a quick tip is that during the earlier waves, treat them as moneymaking times; racking up melee kills or kills with the Lancer's chainsaw and Retro Lancer's bayonet. when players make it through the first 10 waves, they get the 10-point achievement "Welcome to Horde Mode" and the Horde t-shirt for their avatar:
Beast Mode
Beast mode is essentially Horde from Gears 2 in reverse; you spawn as a Locust creature and fight Stranded and COG heroes while on a timer. the timer starts when the first player chooses their Locust. as the picture shows, you can actually play as a Berserker, but only in the later waves once you unlock her. when players either kill enemies or dismantle their defenses, they get a few more seconds added to the timer. when the waves are reached that have the COG heroes in them, the heroes can only be killed by execution or by an instant kill weapon such as the Boomshot.
Beast is a fun addition to the series, but it's somewhat complicated when playing solo. one good tip would be to start as the Savage Drone, because they're equipped with Retro Lancers and can not worry so much about the barriers and just shoot the enemies right over them. then, once enough progress is made to unlock the Berserker, one can just keep spawning as Berserkers and completely demolish the Stranded. when the player finishes all 12 waves, they get the achievement "Welcome to Beast Mode", worth 10 points. they also get the Drone mask for their avatar.
there is also a new Team Deathmatch mode for versus multiplayer, but there's nothing really special about it to get its own review. it's your standard Team Deathmatch mode, just in Gears now.