Evaluating the effectiveness of HUDs and diegetic ammo displays in first-person shooter games

We present an experiment comparing five ammunition display methods in first-person shooter (FPS) games. These included both diegetic (in-game) and heads-up display (HUD) options. HUD displays included a bar, icons, and a counter. Diegetic displays were displayed in-game beside the player´s weapon. Two diegetic displays were evaluated: a number and bullets. We compared the performance offered by each ammunition display and player preference towards each. Results indicate that the diegetic "number-in-game" display performed best both in terms of reload time and shots taken between running out of ammunition and reloading. Participants fired an average of 35% fewer shots after running out of ammo with the number-in-game display than with the worst performing display, icons-on-HUD. Reload time was also 26% faster with the number-in-game display than with icons-on-HUD. The number-in-game display was preferred by 70% of participants.