Using Brain Computer Interfaces (BCIs) as a control modality for games is popular. However BCIs require prior training before playing, which is hurtful to immersion and player experience in the game. For this reason, we propose an explicit integration of the training protocol in game by a modification of the game environment to enforce the synchronicity with the BCI system and to provide appropriate instructions to user. We then dissimulate the synchronicity in the game mechanics by using priming to mask the training instruction (implicit stimuli). We conduct an evaluation of the effects on game experience compared to standard BCI training on 36 subjects. We use the game experience questionnaire (GEQ) coupled with reliability analysis (Cronbach's alpha). The integration does not change the feeling of competence (3/4). However, flow and immersion increase sizably with explicit training integration (2.78 and 2.67/4 from 1.79/4 and 1.52/4) and even more with the implicit training integration (3.27/4 and 3.12/4).