How are the battle scenes

The battle scenes, or firefight scenes are quite impressive given the budget.

Convincing muzzle flashes, wounds, etc.

There is not much blood in the scenes, however, but that is not to do with budget but the actual story. You can't bleed what you can't hit, in other words without ruining the plot.

The scenes are very realistic, however small they were. Fire fights in the bunker were indeed impressive, as the team worked together and relayed information to each other during the fights. Small Mercenary squads need to keep in constant communication in reality, which is shown in the film. The other realistic thing is that the different nationalities prefer different equipment.

The more western and modern approach using a G36K, or some of the more eastern members preferring to use an AK47 and a G36K.

The only gripe I have with the scenes is the ammunition fired and the lack of reloading taken place, but given the camera changes I can understand the speed of reloads would be quicker. The men often had access to a quick change setup on their ammo cartridges (2 taped to the other), and I have seen men able to change cartridge in about 2 seconds and begin firing again, so I guess that could be excused. Though they did fire off over 400 rounds in a very short period per person, which was a bit overkill.

Other than that I was impressed with the battle scenes. Very realistic.